Method and apparatus for heattreating rails



y 1941- H. s. GEORGE 2,242,882

METHOD AND APPARATUS FOR HEAT-TREATING RAILS Original Filed June 8, 1935 2 Sheets-Sheet 1 HARRY S. GEORGE y 1 m c ATTO EY y 1941- H. s. GEORGE 2,242,882

METHOD AND APPARATUS FOR HEAT-TREATING RAILS Original Filed June 8, 1955 2 Sheets-Sheet 2 INVENTOR. HARRY S. GEORGE BY l" ATTORNEY Patented May 20, 1941 METHOD AND APPARATUS FOR HEAT- TREATING RAILS Harry 8. George, Massapequa, N. Y., assignor, by mesne assignments, to Union Carbide and Carbon Corporation, a corporation of New York Original. application June 8, 1935, Serial No.

Divided and this application December 21, 1938, Serial No. 246,960

' 1 Claims. (once-5) This inventionrelates to a method of and apparatus for heat treating and hardening the running or tread surfaces of rails, especially at-rail joints, and more particularly to portable apparatus which can be positioned at the joints for hardening tread surface areas by heat treatment with high temperature heating flames. The

present application is a division of copending application Serial No. 25,567, filed June 8, 1935.

Tread surfaces at the ends of rails at joints in track become battered to a lower level than other portions of the tread surfaces of rails, because at the ends of rails there is no support against aid flow of rail metal at the tread surface. The rate at which tread surfaces of rails become battered, therefore, is greater at rail ends. This lowering of the running or tread surfaces of rails at rail joints increases the effect of the pressure of the rolling traffic by converting it into a downward blow as the wheels pass over rail joints. This action still further increases the rate at which the tread surfaces at the ends of-rails become battered over that of the rest of the rails. For this reason rails, particularly at their ends, are heat treated or hardened to retard the rate of batter and prolong their life so as to reduce operating cost in track maintenance.

Attempts have been made to provide apparatus for heat treating rail tread surfaces by applyingheat and using an external quenching medium, such as water or oil. Although individual hardened areas can be produced when such apparatus is employed, it has been impossible toheat treat tread surface areas of rails in a section of track so .thatall oi' the areas are heat treated substantially'to the same valueof hardness. When an external quenching medium is used it has also been found impossible to obtain hardenedareas which will effectively stand up under present day traffic conditions because of the tendency to produce cracks and to set up internal stresses is reached. Such methods have not proven satisfactory because it is not humanly possible for an operator by visual inspection to heat each rail end to the same elevated temperature. Pyrometric methods have not proven successful partly because of the time delay from the termination of the heat treating operation and the instant the temperature reading can be taken. Addi tional precautions must be taken in applying the heat when a secondary tempering operationis employed and making certain that the desir d temperature is reached. Again attempts have been made t6 determine the temperature by visual inspection. Although attempts have been made to check the drawing temperature by wiping solder across the heated area or by utilizing a pyrometer, these methods have proven neither accuratenor reliable. Former methods have failed, therefore, because of actual damage to the rails, particularly in cracking; non-uniformity in hardness of a wide range existing not only in the individualtread surfaces hardened but also between successive rail joints in track; failure to produce hardness adequate to prevent flow of rail metal. P

It has also generally been the practice to harden the tread surfaces at rail ends by heating a rectangular area. This practice is objectionable because of the abrupt transition between the hardened tread surface area and unhardened area adjacent thereto.

Although not to be limited thereto, the present apparatus is particularly adapted forheat treating or hardening rails by allowing the heated -tread surface areas to cool naturally from an tread surface areas so as to heat the areas to a which, when combined with repeated stresses from service, often results in the eventual cracking of the hardenedsuriaces. This is especially true when a secondary tempering operation is employed because of the extra hazard entailed in the drasticapplication of heat to steel in a' hardened state.

m hardenin'g rails it is important to heat all or theareas substantially-to the same elevated temdetermine when the desired elevated temperature considerable depth, the rate of application and amount and distribution 'of heat being so controlled that the underlying and adjacent mass of the rail willremain relatively cool and exert a quenching effect on the heated surface areas by withdrawing heat therefrom to cool and umformly harden each individual area naturally.

Not only are hardened tread surfaces produced by the present method and apparatusthat will effectively prevent flow of tread surface metal at rail ends when they are subjected to service; but it is commercially practicable with the present method and apparatus to heattreat a number of tread surface areas in a section of track to substantially the same value of hardness. Further, the objection of having the transitionzones between hardened and mihardenedareas extending approximately diagonally across the rail heads.

The objects of the present invention, there- ,fore, are to provide a commercially practicable and successful method of and apparatus for heat treating and hardening tread surface areas,par-,

ticularly at rail ends, with a single application of heat; to heat treat tread surface areas at the ends of rails in such a manner that rolling traffic will not pass abruptly from a hardened to an unhardened portion of a tread surface or vice versa; to provide portable apparatus which' can hollow tubular members/and to provide such apparatus wherein each heat treating operation i i s'eifected in the minimum length of time to I produce heat treated tread surface areas always having substantially the same value of hardness.

The above and further objects and novel features of 'my invention will become apparent from the following description and accompanying q drawings, in which:

Fig. 1 is a perspective view of apparatus em- Fig. 2 is a side'view of the heating unit of the apparatus illustrated in Fig. 1; I Fig. 3 is a sectional view taken at line 3-3 of.

2 to illustrate the position of the nozzles for applying high temperature heating flames to the tread surface areas at the ends of abutting rails forming the'jointf V Fig. '4 is a fragmentary sectional view taken at line 4--4 of Fig. 2 toillustrate the shape of a baille plate and its position relative to the nozzles;

. and

Fig. 5 is a fragmentary sectional view taken at line 5-5 of Fig. 2 to illustrate parts of the apparatus more clearly,

i The apparatus broadly comprises a frame F adapted to extend across a track and rest on the rails, and a heating unit structure A atone end of the frame adjacent a rail of the track. A plurality of nozzles or tips N adapted to be conbodying thisinvention with the apparatus in position at a rail joint ina section of track;

nected to a source of gaseous fuel provide high temperature heating flames for heating tread surface. areas of the rails. The ends of the nozzles and also the heating flames directed from the l nozzles are preferably disposed at the apices of a horizontally planar triangle. The nozzles preferably are pivotally mounted on. the heating unit. A so that they can be oscillated by moving .a

handle H which extends across the track from the heating unit toward the opposite rail. The

5 frame F is of fabricated welded construction and formed of hollow tubular members to provide a portable apparatus which is rigid and strong and also of minimum weight, so that it canreadily i be moved along, a section of track having tread surface areas to be heat treated.

The heating unit A may comprise a hollow rectangular block Ill having supporting legs I Eat each corner thereof, the pairs of legs at each end of the block having a connecting member [2 at their lower ends adapted to rest transversely across the rails l3 and I4 at the ends of which the V tread surface areas are to be hardened. I Nozzles N adapted'to be connected to a source of gaseous 75 at right angles to the lengths of the rails can be avoided by terminating the heat treated areas fuel and carried by the heating unit A are preferably employed as the source of high temperature heat, although it is to be understood that justable longitudinally of the rails l3 and I4 with respect to the other, and both of which are adjustable thereon. In the present embodiment,

'as shown in Figs. 1 and 2, three nozzles N are secured to each manifold'l5 and I6 with two of each group of nozzles disposed above the inside edges H and I8 of the rails l3 and and one of each group disposed above the outside edges l9 and 20 of the rails.

. To the upper sides of the manifoldslfrand I6 are secured hollow tubular connections 2| and 22 which are formed integral with brackets 23 and 24 and to which flexible gas conduits I1 and 18 are detachably secured. The bracket 23 is provided with an opening through which extends a shaft 25'having a handle or handwheel 26 at one endv thereof. The shaft 25 is prevented from moving axially by collars- 21 and 28 fixed to the shaft and bearing'against the side walls of the bracket 23. A threaded outer portion 29 of the shaft 25 extends through a threaded opening in the bracket 24 provided with'a second opening through which extends a guide rod 30 having one end thereof secured to the bracket 23 and extending substantially parallel to the shaft 25.

when the handle 26 is turned, the bracket 24 can be moved toward or away from the bracket 23 to adjust the group of nozzles N attached to the manifold l6 longitudinally of the rails with respect to the group of nozzles N attached to the manifold l5.

The nozzles N, manifold blocks I5 and I6, and brackets 23 and 24 may be pivotally mounted on the block ID by providing an integral hollow sleeve 3| on the bracket 23. The reduced ends 32' and 33 of arms 32 and 33 are adapted to extend into the ends of the sleeve 3I' and the opposite ends thereof are enlarged and provided with openings for movement along vertically disposed studs 34 attached to the ends of theblock I. To adjust the nozzles N atanydesired position with respect to the'tread surface areas being heat treated, a pair of lock nuts indicated at 35 and 36, respectively, is provided on each stud with the nuts adapted to bear against theupper and lower sides of the enlarged ends of the arms 32 and 33. With the construction just described. the block I0 is positioned at a rail joint with the nozzles at the desired elevation. and

the group ofnozzles N secured to the manifold,

I5 at the desired positionvabove the tread surface from the extreme end of the rail l4. .The "handle 26 is then turned to move the manifold operates-with the'nozzles N, the shield preferably being. of a metalor alloy possessing 'highheat' conductivity and capable of dissipating heat Sufflciently rapidly so that it will not melt.

I have found a copper block or plate of substantial' mass suitable for this purpose and, as shown in the drawings, such a copper block B may be disposed longitudinally of the rails and extend downwardlyfrom the manifolds l and I6 to divide the nozzles into two groups. As shown in Fig. 4, one or more studs 39 may be secured to the upper edge of the baflie B and extend through openings in the manifold i5. and the upper end of each stud may be threaded to receive a lock nut 40. The upper edge of the shield B may be slightly undercut, as indicated at 4|, to provide sufilcient clearance for moving the manifold l6 toward and away from the manifold I5. To maintain the shield B in alignment between the nozzles, a' U- haped guide 42 in which the shield slides may be secured to one end of the movable manifold Hi. i

The shield B is preferably of such shape that the side walls thereof are close to the discharge ends of the nozzle N, thereby diminishing the circulation of the flames and surrounding heated air about the nozzles. Since the nozzles or tips generally employed are tapered, the shield B is provided with substantially parallel walls which diverge at their lower ends adjacent the tapered portion of the nozzles to provide a small clearance between the shield and the nozzles. With this arrangement there is less tendency of overheating the nozzles by the flames reflected from the tread surfaces to cause pre-ignition and backfiring of the gaseous fuel delivered to the nozzles, and the necessity of water cooling the nozzles is avoided.

The nozzles N may be oscillated above the tread surfaces of the rails l3 and M by a handle H comprising a hollow tubular member secured to the bracket 23-. The handle H extends upwardly'and across the track to the opposite or far rail 44, so that an operator positioned at the far rail can move the handle to oscillate the nozzles transversely across the rail heads. To.

limit the transverse oscillatory movement that can be imparted to the nozzles N. the bracket 23 is provided with projections .45 and 46 on opposite sides thereof having openings adapted to receive threaded bolts 41 and 48, respectively;

the ends of which are adapted to contact the top surface of the block l0. Lock nuts 49 and 56 are provided on the bolts 41- and 48 to adjust the limit of oscillatory movement that can be imparted to the nozzles N. w

The frame F for supporting the heating unit A on the rails |3 and I4 may comprise tubular members. 5| and 52 having threaded reduced ends which extend through openings in projections extending downwardly from the legs II that are disposed at the inner edges of the "rails |3 and I4, as shown in Fig. 5. The reduced ends of the members, 5| and 52 are adapted to contact the sides of the rail heads and may be provided with lock nuts Na and b which bear against opposite sides of the projections H to position the nozzles between the inner-and outer edges of the rail heads when the apparatus is positioned at a rail joint. The members 5| and 52 extend across the track; converge slightly tow ward each other, and the outer ends thereof are adapted to rest on the opposite rail 44 of the track. The members 5| and 52 are connected intermediate their ends by a cross member 54 and at the extreme endsby a'member 55. A third member 56 extending between the rails of the track is also provided with a threaded re- 3d any valve 5 parallel to the members 5| and 52 and in a vertical plane intermediate these members. The

member 56 terminates approximately above the member 54, and ,from its outer'end two members 59 and 60extend obliquely downward and are secured at their lower.ends to the members 5| and52. Two additional members SI and 62 extend vertically upward from the members 5| and 52 at points adjacent to and spacedfrom the end member 55, the upper ends of which are attached to a plate 63. A reenforcing member '64 extends from the plate -63 to the midpoint of the cross member 54. A U-shaped bracket 65, 'having the arms thereof attached at 66 and 61, respectively, to theupper ends of the studs 33 '20 and 34, is providedto enable the apparatus to be moved readily from joint to joint, one person holding thebracket 65 and another person holding the cross member 55. The different members of the frame are formed of hollow light-weight tubing and are welded together to provide a fabricated rigid and strong- Since it is desirable to control the flow of the combustible gas mixture without disturbing frame structure which is been made a cut-out valve 68, which is mounted on the plate 63, is provided. cut-out valve -68 may be connected to fle le tubing 69 and 18 for supplying gases, such as oxygen and acetylene, to provide the high temperature heating flames at the nozzles N;' and this valve is provided with a single lever 1| for simultaneously controlling the flow of oxy en and acetylene to the nozzles N.

The acetylene gas and oxygengas are delivered from thecut-out 'valve 68 through flexible conduits 12 and '13, respectively, to a mixing chamber 14 which is mounted on the member 58, such mixing chamber having valves provided with handles 15 and 16 for controlling the mixture of oxygen and acetylene. The mixture of oxygen and acetylene is delivered from the mixing chamber to the nozzles N through flexible conduits 11 and 18 and the vertical connections 2| and 22 to themanifolds l5 and I6.

For igniting the combustible gas mixture, at the nozzlesN a pilot burner P may be employed. Such a burner may comprise the end of a me tallic tubing 19 su ported at 80 to the, block I0 adiacent the nozzles N, the tubing extending \through a portion of the hollow tubular member 56 and being connected to a partially open valve having a push button 8|, thevalve being connected to the acetylene supply at the cut-off 0 valve 68 in such a manner that the operation of the lastsmentioned valve will not interfere with the acetylene gas ,deli'vered to the pilot burner. The push button 8| is provid for opening the partially open valve further when 5 it is desired to increase the size of the continu ously burning pilot flame to ignite the gas at -the nozzles N. A triangular-shaped shield 82 ispositioned on the frame F betweentheheat- A ing unit A andcthe opposite endof the apra- 7o r-atus to protect parts of the apparatus and the.

operator from the intense heat ofthe flames To control p the one of. the factors to-be considered in the preduced end adapted to bedetachably secured to ferred method I employ, a'timing device 83 is adjustments after they have once I The inlets of the the heat is a pued, thisbeing ible tubing being provided to provided which may be mounted on the reenforcing member 64 indirect view of the operator as he is facing the heating unit A adjacent the far rail 44.

In order to prevent any improper operation of the track signalling system by positioning the apparatus across the track so as to complete an electric circuit, a rubber sheet 84 is fitted over the tubular members 5| and 52 at the region they normally contact the rail 44, thereby insulating the apparatus from one rail of the track.

The method of operating the heat treating apparatus just described is substantially as-follows;

In heat treating tread surface areas at ra'il joints in a sectionof track, certain preliminary adjustments are made before heat treatingthe first rail joint. The heating unit A is positioned at'- the first railjoint in a section of track so that the threaded reduced ends'of the members 5| and 52 contact and bear against the inner sides of the heads of the rails l3 and I4, and

the lock nuts Ila and llb adjusted to locate the nozzles at the desired position between the inner and outer edges oftherail heads. The tips of the nozzles are then correctly positioned for height above the tread surfaces of the rails, and the group of nozzles N connected to the fixed manifold I5 properly positioned lengthwise of the rail l3 from the extreme end of the rail. With the frame F and heating unit A in their adjusted position, the nozzles N connected to the manifold I 6 may be positioned from the extreme end of the rail II by turning the hand-- wheel 26. Inadjusting the elevation and position of the nozzles a suitable gauge may beemployed.

1| of the cut-out valve 68 then moved to its open position to deliver oxygen and acetylene to the nozzles N. Simultaneously with the lighting of the nozzles-the operator oscillates the nozzles through a small are by moving the handle H up and down. By observing the timing device 83, the length of time the heat is applied to the tread surface areas can be accurately determined, and, at the end of a predetermined length of time,: the lever H of the cut-out valve 68 is moved to its closed position. The apparatus is then moved to the next rail joint in the section of track. Since the preliminary adjust- -ments have already been .made, it is only necessary to position the-nozzl from the extreme ends of the rails. 7 At each rail joint natural cooling effectively cools and hardens the tread surface areas heated.

It -is to be understood that the expression natural' cooling signifies the combined cooling effect of convection and radiation of heat from the rail to the surrounding air plus thefccoling .eifect of theunderlying and adjacent mass of,

the rail which is relatively cool. I have found that the latter effect is much greater than the cool g effect. of air where a relatively small trea surface area of an ordinary rail is heated.

In order to produce hardened areas at rail ends in a; section of track with each tread surface area having substantially the samevalue of hardness,

- certainfactors must be considered in each par-' With the nozzlesproperly positioned above the tread surfaces and from the extreme ends of the rails the threaded bolts 41 and 48 are initially adjusted at the first rail joint to limit the oscillatory movement that can be imparted to the nozzles N by moving the handle H. The position of the nozzles and the limit of their oscillatory movement are such that the gas flames are not directly applied to inner and outer edges nor to the extreme end edges of the rail tread surfaces. The conduction of heat to the extreme side edges and corners of the-tread surfaces from the heated portions adjacent thereto is sufiicient to heat such parts so that uniformity of temperature of the heat treated'areasis attained.

In making the preliminary adjustments-the handles 15 and 18 of the valves of the mixing chamber are adjusted to produce flames having the prop rate of heat output, the flames being adjusted, or example, to be neutral. This adjustment must then be maintained substantially constant? The oxygen and acetylene pressure regulating va1ves, which are connected to the ture, is definite and-so balanced that natural cooling ticular application. For a particular size rail and tread surface area to be hardened, the quantity of'heat thatshould be applied is determined. A

number-of nozzles of proper size are employed with the oxygen and acetylene pressures adjusted so that flames having a substantially constant rate of heat output are produced, the tips of the nozzles being positioned a predetermined height from the tread surfaces of the rails and distance from the railends. Further, the nozzles are so positioned relative to stantially uniformly. An oscillatory movement of determined amplitude is preferably imparted to the nozzles to insure obtaining a uniform dis- 7 tribution of heat.

In addition to the foregoing factors, the length-- uniformly to an elevated temperature and to a predetermined depth, The relation between the heat conductivity of the rail metal, its temperaand the amount and distribution of the heat automatically leaves the heat treated area at the desired hardness without the necessity .of employing an external quenching medium.

sburces of; supply of the gases, are also initially adju' ted to deliver oxygen and acetylene through the onductors 69 and 10 at the proper pressures to the cut-out valve 88. A cylinder of oxygen and 'a number of cylinders ofacetylene connected to a manifold, as well as the regulating valves, may be mounted on a push car adapted to travel along the track, sumcient flex move the appa--- ratus readily from joint to joint.

With the above-described. preliminary adjustments made. the pilot burner P is lighted and the apparatus is ready for heat treating the first rail joint. -The push button 8| is operated to increase the size of the pilot flame, and the lever tors to be considered in hardening One important feature of this method ofusing the apparatus of the invention to heat treat rail tread surfaces which makes it commercially'prac ticable and successful is that in successive joints in a section of track uniformity of temperature heretofore there has been track. Not only are the tread surface areas-heat treated in this manner of adequate hardness, but the structure and physical condition of the tread surface metal is of such a character that it will not-chip nor flow when subjected to service.

The foregoing emphasis on the different facmgmo the pnesent rails accord out that accurate method hasibeen and controlled hardening is not each other that thegflames are applied to heat each tread surface area submade to point carburized metal is removed by grinding.

obtained by applying heat at random and then allowing the heated tread surface areas to cool naturally; nor by the former methods which employ pyrometers to check temperatures. The various factors are initially considered for a given set of track conditions, and, after they have been determined, any number of rail ends can be hardened by heat treatment without relying upon the judgment of an operator or upon instruments which, while suitable for shop practice, are not feasible for track work.

Although it is most desirable to harden new rails to anticipate wear and flow of tread surface metal, the life of used rails can be prolonged by heat treating the ends of such rails. New rails present a unique problem because they generally have a thin layer of decarburized metal caused by adherent scale during the rolling operation in the steel mills. Although the decarburized surface layer, which may vary from .02 to .04 inch in thickness, does not impair the mechanical value of rails, the lower carbon content of the surface layer seriously diminishes the hardening ability of the metal, Although the present apparatus effectivelyhardens the underlying normal metal to the desired value and depth, testing of the decarburized surface affords no accurate measure of the hardness produced.

In heat treating new rails in a section of track with the present method, therefore, the various factors are determined by providing a ,test rai joint formed of rails having the same composition and general dimensions as the rails in the section of track, and the surface layer of de- The necesary adjustments are then approximated, and the test joint hardened by applyiiig the heat for a definite interval of time. The value of hardness and the uniformity of its distribution can immediately be determined by a Scleroscope assoon as the test joint has cooled, and, if the desired hardness is not produced, the adjustments can be'varied and the test joint hardened again.

When the proper hardness is produced in the test joint, the apparatus can be employed to harden tread surface areas at the ends of rails in a section of track. After these rails have-been subjected to service the decarburized surface layer is removed and the hardened surface revealed which has been resisting deformation. To make certain the apparatus is being properly operated, it is advisable to heat treat a short portable test joint about every one-half mile of track.

Sometimes it is desired to heat treat after it y is knowrrthat rails in a section of track have had the decarburized surface layer removed through abrasion by rolling traflic, and in such cases-the resulting hardness produced at tread surface areas' can immediately be determined by test, In such cases it is also preferred, however, to check and adjust the apparatus at. a test joint in the same manner as described above in heat treating new rails. I

Ordinary rails usually contain from approximately .55 to ..90 per cent carbon and a similar amount of manganese, and have ahardness varging from about 250 to 286 Brinell. With t e inches are secured to each manifold and supplied with acetylene and oxygen, the acetylene pressure at the regulator being about 15 to 20 pounds per square inch with the valve wide open, and the oxygen being supplied at a rate to produce flames of the character desired, such as neutral, for example. The gas pressures will vary with the size of hose and connections used, The nozzles are positioned about inch above the tread surfaces of the rails, and it is tobe under stood that a small variation in the elevation of the nozzles, such as V; inch, will affect the hardness desired unless other factors are varied; to compensate therefor. L

The nozzles connected to each manifold are positioned with the two nozzles parallel to the end edges about 1%. inches apart. The position of these nozzles from the extreme ends of the rails is dependent upon the opening at the rail joint, the position of the nozzles varying from about .63

from the ends of the rails when the opening is .12 inch or greater to about .5 inch when the gap is .06 inch or less. The two nozzles disposed adjacent'the inner edges l1 and I8 of the rails are s acednabout inch apart, the nozzle the gr ter distance from the endsof the rails bein about /8 inch nearer the inner edges of the rails. These spacings of the nozzles have been found suitable for rails weighing about 112 pounds per linear yard and can be employed for heat treating full-headed rails. For heat treating rails heavier and lighter than 112 pounds per linear yard, other manifolds or blocks are em- ,ployed with the nozzles spaced suitable distances from each other to produce the desired hardness in rail tread surface areas;

The flames are adjusted'with the inner or luminous? cones disposed about ,4; inch above the rail tread surfaces, and an oscillatory movement of about /4 inch imparted to the tips of the nozzles. As suggested above, for a 112 pound I rail, the nozzles transverse to. the rail head should be about 1%, inches apart. an oscillation of about inch, the area directly heated is about 2 inches wide. The head of a rail of this weight is between 2% and 3 inches wide, hence the part directly heated 'is limited to about to 75% of the full Width. of the rail head, and is spaced inwardly from both side edges of the rail. Adouble swing or rocking movement of the nozzles takes about one second, and for the present .application the heating flames are applied for about 15 seconds. Every one of the factors mentioned has some influence in the hardness produced, and for this reason it is necessary to predetermine the proper value of each factor experimentally by heat treating above-described apparatus the Brinell hardness a test joint before heat treating rail ends along a section of track. Even variations in the spacing of the rails at a joint afiectsthe final result because the heat has access to the ends as well as the surfacesof the rails inv an open joint whereas this is not .truein a closed joint. Hence in the former instance, the .heat'input is greater than in the latter for the same. length of heat treatment. For 112 pound rails the heating time is about 14 to 15 seconds where the gap between rails exceeds about .125 inch, about 17 to 18 seconds'for' narrower gaps, and about 20 seconds for tight joints. To'obtain a more uniform in- Y terval of time-for heat treating successive rail joints, it is desirable to initially slottight joints to provide a minimum gap at joints in a section of track. w

The tread surface areas Thus, with I hardened are trapezoidal in shape and extend back from the ex-' treme .end of the rail about 1 inch at the ou'ter edge and about 1% inches at the inneredge. The size of the areas hardened can be varied for different sized rails. [The diagonal boundaries produced at the transition zones, indicated by 4 the dotted lines 85 in Fig.3, provide hardened areaswhich are longest at the edges of the rail 'heads where the tendency of the rail metal to wear and flow is usually greatest. Further, such areas are the smallest areas which willgive sufllture of the'unhardened steel.

From an observation of the performance of rails of standard composition .under modern trafiic conditions, I have discovered that heat treated tread surfaces of rails should possess a hardness of at least 58-60 Scleroscope after being subjected to service if they are to withstand the tendency to flow at their ends, at joints.- In order to attain this hardness the heat treated tread surface must have a Scleroscope hardness of about 50 to 52 after heat treatment and before they are subjected to service. It has been found that this Scleroscope hardness increases to about 60 after being .s'ubjected'to service or cold work, as it is commonly called. Thus, the hardening due to' cold work further tends to prevent deformation and wear and therefore constitutes a beneficial or protective action. The Scleroscope hardness of about 50 to 52 corresponds to a Brinell hardness of about 350, and it has been found that thev increase of hardnessdue to cold work being very shallow, is not indicated by the Brinell test so that it remains sub- 'stantially unchanged.

- Ordinary rails readily respond to heat treatment when cooled naturally from a hardening elevated temperature. By heat treating tread surface areas with the present apparatus and permitting the areas to cool and harden naturally, it has beenpossible to obtain a hardness as high as 420 Brinell. .The corresponding- Scleroscope hardness is about 62 and increases a to about 68- 70 after the rail has been subjected to service. Rail tread surfaces heat treated to 55 this value of hardness are entirely satisfactory and will efiectively withstand rear end flow when subjected to present day traffic conditions.

It will thus be seen that the present method and portable apparatus canbeeffectively employed to heat treat a number of tread surface areas in a section of track to substantially the same value of hardness. By making the hardened areas-approximately tr'apezoidal'of triangula'r-shaped there is the further economy in the amount of heat requiredascompared with pro? ducing hardened areas of rectangular shape to' -obtain the same effective length of hardening along rails.

While I have shown and described a particular embodiment of my invention,..i t willbe obvious to those skilled in the art that modifications may be made, and that certain features may be used independently of othersin heat flames or the electric are, without departing from. the spirit and scope of my invention.

What is claimed is: 1. Apparatus for heat treating tread surfac 6 areas of rails comprising in combination, a supporting block adapted to rest upon'the tread surface of one rail of a track; a frame secured to said block and extending transversely of said track, said frame comprising lower elongated 10 hollow tubular members and an upper elongated hollow tubular member, each of said members being adjustably secured at one end to said block, and vertically extending means connecting the oppositeend of said upper member to said lower members; electrically insulating means secured' 'to the opposite ends of said lower members and adapted to rest upon the other rail of said track; a first group of heating nozzles pivotally mounted upon said block; a second group of heating nozzles slidably mounted upon said first group of nozzles, said nozzles being disposed abovethe tread surface area of said one rail; means for adjusting said second group of nozzles longitudinally' of said one rail with respect .to'said zd'firstgroup of nozzles; means mounted on' said block for adjusting both groups of nozzles verti cally withfrespect to said rails; a blowpipe secured to said upper member and operatively connected' to said nozzles for supplying a combustible gas mixture thereto; shut-ofi .valve means mounted on said frame adjacent the other rail of said track and operatively associated with said blowpipe for controlling the supply of a combustible gas and'a combustion-supportinggas thereto; a

handle rigidly secured to said first groupof noz-- zles and extending transversely of said track to a point adjacent, said shut-off valve, said handle be-- 7 ing adapted to oscillate said nozzles transversely of the tread surface of said one rail; and adjust- 0 able means for limiting the amplitude of oscillamaterial secured to said frame between said block second handle means connecting said opposite ends of said lower members, whereby said apparatus is manually transportable.

4. Apparatus for heat treating-tread surface areas of rails comprising, in combination, a

frame adaptedto extend transversely and rest .upon a pair of-rails forming part of a track sec-.

tion; a support, secured to said frame adjacent %-one end thereof; a plurality of heating units piv-.

- otally mountedlon said-support and disposed adjacent said tread surface areas; control means for regulating the amount of heat delivered by said heating units, said .control means 1 being mounted on the opposite end of said frame; means for oscillating said heating units with respect to said tread surface areas, said oscillating means being. mounted on said support in such. amanner as to be operable from a point closely 1 adjacent said control means, whereby an operator'can readily control said heat treatin'gfrom -a single position adjacent the end of said frame opposite said support;- and a shield of heat-resisting material secured to said frame intermediate the ends thereof to protect the-operator from the heat delivered by said heating units.

5. Apparatus-for heat treating tread surface areas [of .rails' comprising the combination -'of a treating tread surfaces of rails either withgas support adapted to rest upon the tread surface between said sources of heat of a rail: at least two sources of heat so mounted upon the support as to be disposed above the tread surface of the rail; means for holding said sources in a flxed position relative to each other; means for adjusting and varying the distance in a direction longitudinally of the rail; means for imparting to the said sources of heat an oscillatory movement in a direction transverse to the length of the rail; and adJustable means for limiting the amplitude of the oscillatorymovement'that can be imparted to said sources of heat; said support being positioned adjacent the abutting ends of a pair of rails and one of said sources of heat being positioned above the tread surface of each of said rails adjacent the end thereof, at least one of said sources of heat comprising means for directing-at least three high temperature heating flames against the tread surface of a rail. said three heating flames being disposed at the apices of a triangle with one side of said triangle substantially parallel to the end of said rail and another side of said triangle substantially parallel to an edge of said rail, whereby said heating flames, upon oscillation transversely of said rail,

will heat a tread surface portion extending longi-.

tudinally of said rail and having a boundary portion spaced from the end of said rail which extends in a diagonal direction transversely of the rail tread surface.

- 8. Apparatus for heat treatin a tread surface area of a rail comprising heating means for directing a group of at least three high temperathe tread surface of a rail a group ture heating flames against the tread surface of a rail; means for positioning said heating means in operative relation to the tread surface of said rail with said three heating flames disposed at the aplces of a triangle andwith one side of said triangle substantiallyparallel to an edge of saidrail and another side'of said triangle substantially transverse to an edge of said rail; and means for oscillating said heating means to move said heating flames transversely of said rail within limits defined by the edges of said rail, so as to heat'a tread surface portion extending longitudinally of said rail but having at one end thereof a boundary portion which extends in a diagonal direction transversely of the tread surface of said rail.

'I. A method of heat treating a tread surface area of a trail which com rises directing against I of high temperature heating flames positioned so that at least three heating flames are disposed at the apices of a triangle, with one side of said triangle disposed substantially parallel to an edge of said rail and another side of said triangle disposed substantially transversely to an edge of said rail;

and oscillating said heating flames y ofsaidrailbutwithinlimitsdeflnedbytheedges ofsaidraihsoastoheatatreadsurfaceportioii extending longitudinally of said rail but having at one end thereof a boundary portion which extends in a diagonal direction the tread surface of said rail.

HARRY S. GEORGE. 

